잔물땡땡이(Hydrochara affinis: Hydrophilidae, Coleoptera) 유충의 모기 2종(Culex pipiens molestus 및 Ochlerotatus togoi)에 대한 실내조건에서의 섭식효율 및 선호도

Abstract

Predation efficiency and preference of the hydrophilid water beetle, Hydrocharaaffinis (Coleoptera: Hydrophilidae), larvae on two mosquito species, Culex pipiens molestus andOchlerotatus togoi, were tested under laboratory conditions. Experiments were conducted in atransparent cylindrical plastic container (diameter, 100 mm; height, 40 mm; water level, 15 mm)for 24 hours (16 h, light; 8 h, dark) at 25 C. The predation efficiency of H. affinis on mosquitolarvae was investigated under various prey conditions (1, 2, 4, 8, 16, 32, 64, and 128 larvae) withfive replicates. Further, in order to investigate the prey preference on two mosquito species, each32 larvae of C. pipiens molestus and O. togoi were provided simultaneously for the first instarlarva of H. affinis with 5 replicates. As a result, the predation curves of H. affinis on two mosquitospecies were logarithmic; and the number of consumed prey increased as the number of predatorinstars were increased. As predicted from the predation curves, the estimated maximum numberof C. pipiens molestus and O. togoi consumed by a third instar larva of H. affinis per a day was926 and 304 larvae, respectively. As predicted from the Holling’s disk equation, the differences inconsumed prey number between predator instars and prey species were caused by handling time rather than attack rate. Handling time decreased rapidly as the predator larvae grew, and that ofO. togoi was twice longer than that of C. pipiens molestus.